Tuition deduction

No, you cannot claim an education credit or deduction for your daughter's tuition if she is not your dependent. Your daughter can claim the credit or deduction for the tuition that you paid, if she meets the other requirements for claiming the credit or deduction. It's treated as if you gave her the money and she used it to pay the tuition.

"not able to claim her because of her earnings"

That's probably not so.

There are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, student status, a relationship test and residence test. Only a QC qualifies a taxpayer for the Earned Income Credit. They are interrelated but the rules are different for each.

A child of a taxpayer can still be a “Qualifying Child” (QC) dependent, regardless of his/her income, if:

1. He is under age 19, or under 24 if a full time student for at least 5 months of the year, or is totally & permanently disabled
2. He did not provide more than 1/2 his own support. Scholarships are considered third party support and not as support provided by the student.
3. He lived with the parent (including temporary absences such as away at school) for more than half the year

So, it doesn't matter how much he earned. What matters is how much he spent on support. Money he put into savings does not count as support he spent on him self.

The support value of the home, provided by the parent, is the fair market rental value of the home plus utilities & other expenses divided by the number of occupants.

Furthermore, there is a rule that says IF somebody else CAN claim him as a dependent, he is not allowed to claim himself. If he has sufficient income (usually more than $12,200), he can & should still file taxes. In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section.  TT will check that box on form 1040.

Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.

If he/she has filed a return, claiming himself, he will need to file an amended return, unclaiming himself, so that you can claim him. You do not need to wait until his amended return is fully processed, to claim him on your return. But, you cannot e-file. You will have to mail in a paper return.

With the tax law change, effective 2018, most students will get the same refund whether they claim themselves or not. The personal exemption has been eliminated and the standard deduction increased.

Furthermore,  a full time unmarried student, under age 24, is only eligible for the refundable portion of the American Opportunity Credit , on his own return,  if he supports himself by working (more than half his support from earned income).

If she does not meet the QC rules, then she must have less than $4200 of income to be a standard dependent.  

See full rules at: https://turbotax.intuit.com/tax-tools/tax-tips/Family/Rules-for-Claiming-a-Dependent-on-Your-Tax-Return/INF12139.html

"because of her earnings"

More than likely, her earnings have nothing to do with it. In order to qualify to claim your daughter as your dependent, the following requirements have to be met. No more. No less.

If the student:

Is under the age of 24 on Dec 31 of the tax year and:

Is enrolled in an undergraduate program at an accredited institution and:

Is enrolled as a full time student for any one academic semester that begins during the tax year, (each institution has their own definition of a full time student) and:

the STUDENT did NOT provide more that 50% of the STUDENT’S support (schollarships/grants received by the student ***do not count*** as the student providing their own support)

Then:

The parents qualify to claim the student as a dependent on the parent's tax return . Period, End of Story. But one thing I want to point out here. The parents *QUALIFY* to claim the student. The parents are *NOT* required to claim the student as a dependent. But even if they don’t, since they *qualify* to claim the student, then if the student will be filing their own tax return the student is *REQUIRED* to select the option for “I can be claimed on someone else’s return”.  To reiterate:

If the student qualifies to be claimed on the parent’s tax return, then the student can not take the self-exemption on their own tax return, no …matter…what.

Also take note that in the above requirements there is no income limit for the student. The student could earn a million dollars (literally!) and still qualify as your dependent. So the claim that you can't claim her as your dependent because of her earnings is not a valid claim, if all the other conditions are met.